A New Relict Species of Slender Salamander (Plethodontidae: Batrachoseps) with a Tiny Range from Point Arguello, California

Samuel S Sweet,Elizabeth L Jockusch

doi:10.1643/h2020027

Abstract

Among western North American amphibian lineages, the plethodontid salamander genus Batrachoseps has undergone the most extensive radiation. Here we describe a new species in the genus from the vicinity of Point Arguello, central California. This lineage falls within the B. pacificus group, but it is differentiated from other species in the group by both molecular sequence data and morphology. It is geographically disjunct from its close relatives, with a tiny range in unlikely habitat along a narrow strip of the Pacific Coast, where it is entirely surrounded by B. nigriventris, a distant relative. Although intraspecific molecular variation is almost entirely absent, some population structure was detected across the 4 km extent of its range. Because of its tiny range and limited genetic variation, the impacts of any potential modifications to its known habitat should be evaluated to ensure the species' continued conservation.

Highlights

Among western North American amphibian lineages, the plethodontid salamander genus Batrachoseps has undergone the most extensive radiation
Holotype.—MVZ:Herp:293138, adult male, collected under boards lying against the northwest wall of the abandoned U.S Coast Guard housing block at Point Arguello on Vandenberg Space Force Base, Santa Barbara County, California, 34.588N, 120.648W, 32 m elevation, Samuel S
The description of B. wakei brings to 23 the number of taxa recognized within the genus Batrachoseps, 22 species and a morphologically divergent subspecies within B. major that is sometimes treated as a species, B. m. aridus; nine of these taxa belong to the B. pacificus group, making it the most diverse of the five subgeneric groups recognized

Summary

Introduction

Among western North American amphibian lineages, the plethodontid salamander genus Batrachoseps has undergone the most extensive radiation. In many cases, species discovery results from molecular analyses that show high genetic divergence or other evidence of reproductive isolation among known populations previously classified as a single species (Jackman, 1998; Shaffer et al, 2004; Kuchta, 2007; Feldman and Hoyer, 2010; Jackson et al, 2017; Bingham et al, 2018), other cases involve the discovery of distinctive new taxa (Kohler et al, 2005; Mead et al, 2005; Graham et al, 2018) Both processes have played substantial roles in the large increase in number of recognized amphibian species (Kohler et al, 2005), including in the plethodontid salamander genus Batrachoseps. The geographic isolation from close relatives, tiny known range, and near absence of genetic diversity suggest that this lineage is an evolutionary relict

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Conclusion